Department of Maternal and Pediatric Sciences, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
BMC Infect Dis. 2010 Oct 24;10:305. doi: 10.1186/1471-2334-10-305.
Although the most frequent extra-pulmonary manifestations of respiratory syncytial virus (RSV) infection involve the cardiovascular system, no data regarding heart function in infants with bronchiolitis associated with RSV infection have yet been systematically collected. The aim of this study was to verify the real frequency of heart involvement in patients with bronchiolitis associated with RSV infection, and whether infants with mild or moderate disease also risk heart malfunction.
A total of 69 otherwise healthy infants aged 1-12 months with bronchiolitis hospitalised in standard wards were enrolled. Pernasal flocked swabs were performed to collect specimens for the detection of RSV by real-time polymerase chain reaction, and a blood sample was drawn to assess troponin I concentrations. On the day of admission, all of the infants underwent 24-hour Holter ECG monitoring and a complete heart evaluation with echocardiography. Patients were re-evaluated by investigators blinded to the etiological and cardiac findings four weeks after enrollment.
Regardless of their clinical presentation, sinoatrial blocks were identified in 26/34 RSV-positive patients (76.5%) and 1/35 RSV-negative patients (2.9%) (p < 0.0001). The blocks recurred more than three times over 24 hours in 25/26 RSV-positive patients (96.2%) and none of the RSV-negative infants. Mean and maximum heart rates were significantly higher in the RSV-positive infants (p < 0.05), as was low-frequency power and the low and high-frequency power ratio (p < 0.05). The blocks were significantly more frequent in the children with an RSV load of ≥100,000 copies/mL than in those with a lower viral load (p < 0.0001). Holter ECG after 28 ± 3 days showed the complete regression of the heart abnormalities.
RSV seems associated with sinoatrial blocks and transient rhythm alterations even when the related respiratory problems are mild or moderate. Further studies are needed to clarify the mechanisms of these rhythm problems and whether they remain asymptomatic and transient even in presence of severe respiratory involvement or chronic underlying disease.
虽然呼吸道合胞病毒（RSV）感染最常见的肺外表现涉及心血管系统，但尚无系统收集有关 RSV 感染引起的毛细支气管炎患儿心脏功能的资料。本研究旨在验证 RSV 感染相关毛细支气管炎患者心脏受累的真实频率，以及轻症或中症患儿是否也存在心脏功能障碍的风险。
共纳入 69 名 1-12 个月龄、在标准病房住院的健康婴儿，采用经鼻咽拭子采集标本，用实时聚合酶链反应检测 RSV，同时抽取血样检测肌钙蛋白 I 浓度。所有患儿入院当天行 24 小时动态心电图监测，并进行超声心动图全面心脏评估。在入组后四周，由对病因和心脏发现均不知情的研究者对患儿进行重新评估。
无论临床表型如何，RSV 阳性患儿中有 26/34 例（76.5%）和 RSV 阴性患儿中有 1/35 例（2.9%）存在窦房结阻滞（p<0.0001）。26 例 RSV 阳性患儿中有 25 例（96.2%）24 小时内阻滞反复发作超过 3 次，而 RSV 阴性患儿中无一例发生。RSV 阳性患儿的平均心率和最大心率均显著高于 RSV 阴性患儿（p<0.05），低频功率和低、高频功率比值也高于后者（p<0.05）。病毒载量≥100,000 拷贝/ml 的患儿中阻滞更为频繁（p<0.0001）。28±3 天后的动态心电图显示心脏异常完全消退。
即使相关呼吸道问题较轻或中等，RSV 似乎也与窦房结阻滞和短暂的节律改变相关。需要进一步研究以阐明这些节律问题的机制，以及即使存在严重的呼吸道受累或潜在的慢性疾病，它们是否仍为无症状和短暂的。
